"Solving Inter-Floor Noise with Technology" Patent Trends in Inter-Floor Noise Reduction

 

Is enduring inter-floor noise the only answer?

 Noise from children running, furniture being moved late at night, and other daily activities often triggers conflict between neighbors. In Korea, where apartment living is especially common, inter-floor noise has become an everyday source of stress for many residents. According to a survey by the Ministry of Environment, complaints related to inter-floor noise have more than doubled over the past five years. Is there no fundamental solution to this issue? In this issue, we explore patent technologies and trends aimed at mitigating inter-floor noise.

Major Causes of Inter-Floor Noise

Inter-floor noise is more than simple inconvenience; it can cause psychological stress, sleep disturbance, depression, and even anger. What types of noise typically arise in apartment buildings?

 Since inter-floor noise originates from various sources, blocking it entirely at the source is extremely difficult. Therefore, incorporating noise-reduction measures during the construction phase is often the most effective solution. With this in mind, major construction companies in Korea have been investing heavily in developing new technologies to prevent and reduce inter-floor noise. Below are several noteworthy examples.

Active Inter-Floor Noise Reduction Device

 Lotte E&C, in collaboration with acoustic engineering company Siren Acoustics, has been studying a technology inspired by noise-canceling systems used in audio devices. When an impact occurs in the upper unit, a vibration sensor installed beneath the ceiling detects it and converts the impact into an electrical signal. This signal is then transmitted to a “muter,” which emits counter-vibrations to cancel out the impact noise. The muter is a system that integrates vibration sensors, signal-processing modules, and vibration-control components. Among these, the vibration sensor plays the most critical role.

 A key advantage of this technology is that it can be easily installed within ceiling finish layers, making it suitable not only for newly constructed buildings but also for retrofitting existing apartments.

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KR10-2025-0045169, Method and apparatus for installing noise cancellation device

A Breakthrough for Heavy Impact Noise: Noise-Reducing Mortar

 At the core of this technology is noise-reducing mortar, also known as viscoelastic mortar, which demonstrates excellent performance in absorbing impact energy. While traditional floating-floor structures typically use lightweight concrete or standard mortar layers, this method replaces them with viscoelastic mortar.

A floating-floor structure suspends the floor finish on resilient materials to prevent noise from being transmitted into the building. While effective for reducing lightweight impact noise (such as small objects falling or light footsteps), this structure is inherently vulnerable to heavy impact noise because the floor finish acts as a mass and cushioning layer acts as a spring, forming a vibration system.

However, incorporating a viscoelastic mortar layer with superior damping properties allows this structure to effectively absorb not only lightweight impact noise but also heavy impact noise.

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KR10-2771831, Gelatinizing mortar compositions and viscoelastic dampening floating floor construction for floor impact sound reduction using the same

Reducing Noise With a “Sandwich-Type Cushion Mat”

 DL E&C, a leading developer of noise-control technologies, has created a new cushion mat for inter-floor noise reduction. Designed to be installed between the concrete slab and the mortar layer, this mat features multiple rows of receptacle spaces that house sound-absorbing inserts. By adding these inserts, the composite cushion panel gains enhanced sound-absorption capability, making it possible to control resonance that occurs during floor impacts.

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KR10-2025-0066526, Composite absorbing panels for reducing floor impact sound

 By using this cushion mat, the composite panel delivers both damping and absorption performance, while the internal sound-absorbing inserts provide additional resonance-absorption effects. As a result, this system can effectively reduce impact noise across a wide frequency range, from lightweight to heavy impact noise.

Inter-Floor Noise Is No Longer an Issue of Personal Endurance, but a Technical Challenge,

 According to Statistics Korea’s 2023 Population and Housing Census, apartments accounted for 64.6 percent of all housing types. This means roughly 6 out of 10 people in Korea live in multi-unit apartment buildings, making inter-floor noise a widespread social issue rather than a matter confined to individuals.

As we've seen in the technologies discussed today, construction companies are now focusing not only on building safely but also on developing solutions that reduce and prevent inter-floor noise. With continued technological advancement and new patent-based innovations, we can look forward to quieter and more comfortable living environments in the future.